1. Technical Field
Aspects of this document relate generally to audio amplifiers.
2. Background Art
The requirements of a modern guitar amplifier are to be able to operate in two modes: a “clean” mode and an “overdrive” mode. In a clean mode, the amplifier passes the signal from the guitar with minimal changes or distortion. In an overdrive mode, the amplifier intentionally creates harmonic distortion from the signal to create classic rock or heavy metal sounds. Overdrive mode originated in vacuum tube amplifiers, which have an ability to gracefully enter and exit from the overload zone. Most transistors and transistor amplifiers abruptly distort and take time to recover, resulting in an inferior sound. Some complicated transistor amplifiers have been able to replicate parts of the vacuum tube sound, but are unable to do both “clean” and “overdrive” with a smooth transition between them.